SALT LAKE CITY — The U.S. Forest Service says it supports one of the last U.S. ski resorts to prohibit snowboarding in a court battle over a ban that snowboarders call discriminatory.

The decision by the Alta ski area to promote a snowboarder-free experience to lure skiers and keep them safe is a rational rule that violates no constitutional rights, attorneys for the Forest Service said in court arguments filed this week.

“Even if Plaintiffs established that they are similar to skiers and have been treated differently, they have failed to show that the federal defendants’ treatment of them was irrational,” Forest Service lawyers wrote.

Four snowboarders filed the lawsuit in federal court in January. They’re claiming discrimination on national forest lands that make up most of the Alta ski area in the mountains east of Salt Lake City. The U.S. Forest Service was named as a defendant in a lawsuit, in which the snowboarders argue the ban violates the promise of equal treatment under the 14th Amendment.

The legal back-and-forth has reignited a long-festering culture clash on the slopes between skiers and snowboarders.

The new Forest Service brief comes a week after the ski area’s lawyers said that the lawsuit degrades the U.S. Constitution and should be thrown out.

Jon Schofield, an attorney for the snowboarders, said both filings mischaracterize the complaint, confuse applicable law and avoid the fact that Alta discriminates against snowboarders based on an inaccurate stereotype. Schofield said they’ll address the issues fully in an upcoming brief.

“Before bringing suit, we considered every issue raised in these motions, and we believe the case rests on solid legal ground,” Schofield said.

Under a 40-year permit issued to Alta by the Forest Service in 2002, the ski area is allowed to restrict any type of skiing device that creates an unnecessary risk to other skiers.

The Forest Service said it agrees with Alta that the way snowboarders slide down the slopes is a legitimate safety concern for skiers. In a filing last week, Alta attorneys explained that skiers find the slopes at Alta more peaceful, safe and enjoyable because they don’t have to worry about being hit by snowboarders whose sideways stance leaves them with a blind spot that can make their wide, sweeping turns a danger to others on the slopes.

“These differences create safety concerns that can be avoided or minimized by not allowing snowboarders,” Forest Service lawyers wrote in the new filing.

Alta is one of 120 ski resorts that has a permit to use Forest Service land, the court brief says. The agency’s lawyers say they are aware of Alta’s snowboarding prohibition but argue the agency was not part of the decision to enact the ban and does not make a profit from it.

Based on a congressionally mandated formula, Alta paid the Forest Service between $305,000 and $474,000 each of the past five years. That represents less than 1 percent of the Forest Service’s annual budget, their attorneys said.

The two other resorts that ban snowboarding are Deer Valley, also in Utah, and Mad River Glen in Vermont.